Conventionally, an electrically-heated window sheet material having a transparent conductive film is known (see for example, Patent Document 1). Bus bars are connected to both ends of a transparent conductive film formed in the electrically-heated window sheet material. One bus bar is connected to a direct current source whereas the other bus bar is grounded. When electricity is allowed to flow through the transparent conductive film, the transparent conductive film generates heat, so that fog (water drops) or the like formed on the electrically-heated window sheet material can be removed. Because it is difficult for electromagnetic waves to be transmitted due to the forming of the transparent conductive film, Patent Document 1 discloses multiples openings systematically arranged to allow electromagnetic waves of a predetermined frequency to be transmitted.